The applicant?s career goal is to become an independent investigator, capable of developing and testing interventions and programs to improve patient safety. He aspires to become an expert in the relationship between service quality and medical error, understanding in a methodologically rigorous fashion how patients can help clinicians to prevent iatrogenic injuries, improve clinical outcomes, and enhance patients? own health care experiences. The proposal includes three projects: The first relies on inpatients to report on the prevalence and type of medical errors; its objective is to describe the epidemiology of patient-reported medical errors among inpatients. The second study assesses whether ambulatory patients can identify adverse events due to medications through an internet-based electronic mail query. This study will help both to characterize the prevalence and type of outpatient adverse drug events and to assess the value of patient reporting as a mechanism to improve the quality of care. The third project focuses on the hospital, rather than on the patient, as a unit of analysis. It links consumer satisfaction surveys with complication rates identified by computerized screening of administrative data. This analysis broadens the approach to patient participation in safety by assessing whether organizations that provide patient-centered care also produce fewer complications than expected.